Method of manufacturing semiconductor device, and recording medium

ABSTRACT

A substrate processing apparatus comprising: a substrate process chamber having a plasma generation space where a processing gas is plasma-excited and a substrate processing space communicating with the plasma generation space; a substrate mounting table installed inside the substrate processing space and for mounting a substrate; an inductive coupling structure provided with a coil installed to be wound around an outer periphery of the plasma generation space; a substrate support table elevating part for raising and lowering the substrate mounting table; a gas supply part for supplying the processing gas to the plasma generation space; and a controller for controlling the substrate support table elevating part, based on a power value of a high-frequency power supplied to the coil, so that the substrate mounted on the substrate mounting table is positioned at a target height according to the power value and spaced apart from a lower end of the coil.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of Ser. No. 16/136,943 filed Sep. 20,2018 which is a bypass continuation application of internationalapplication No. PCT/JP2017/012666 having an international filing date ofMar. 28, 2017 and designating the United States, the internationalapplication being based upon and claiming the benefit of priority fromJapanese Patent Application Nos. 2016-084506 and 2016-214304, filed onApr. 20, 2016 and Nov. 1, 2016, respectively, the entire contents ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a method of manufacturing asemiconductor device, and a non-transitory computer-readable recordingmedium.

BACKGROUND

In recent years, a semiconductor device such as a flash memory or thelike tends to be highly integrated. Along with this, the size ofpatterns has been remarkably miniaturized. When forming these patterns,as one of various manufacturing processes, a process of performing apredetermined process such as an oxidizing process or a nitridingprocess on a substrate may be performed in some cases.

For example, there is known a technique which modifies a surface of apattern formed on a substrate using a plasma-excited processing gas.

However, when processing a substrate by plasma-exciting a processinggas, if the density of plasma generated on the surface of the substrateis uneven, the surface of the substrate is not uniformly processed.Thus, variations may occur in the performance of the semiconductordevice manufactured from the substrate.

SUMMARY

The present disclosure provides some embodiments of a technique capableof reducing unevenness in the density of plasma generated on a substratesurface and improving the in-plane uniformity of a substrate process,when performing the substrate process by plasma-exciting a processinggas.

According to one embodiment of the present disclosure, there is provideda method of manufacturing a semiconductor device, including: loading asubstrate into a substrate process chamber having a plasma generationspace in which a processing gas is plasma-excited and a substrateprocess space communicating with the plasma generation space; mountingthe substrate on a substrate mounting table installed inside thesubstrate process space; adjusting a height of the substrate mountingtable so that the substrate mounted on the substrate mounting table islocated at a height lower than a lower end of a coil, the coilconfigured to wind around an outer periphery of the plasma generationspace so as to have a diameter larger than a diameter of the substrate;supplying the processing gas to the plasma generation space;plasma-exciting the processing gas supplied to the plasma generationspace by supplying a high-frequency power to the coil to resonate thecoil; and processing the substrate mounted on the substrate mountingtable by the plasma-excitation.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic sectional view of a substrate processing apparatusaccording to an embodiment of the present disclosure.

FIG. 2 is an explanatory view for explaining a plasma generationprinciple of a substrate processing apparatus according to an embodimentof the present disclosure.

FIG. 3 is a view showing a configuration of a control part (controlmeans) of a substrate processing apparatus according to an embodiment ofthe present disclosure.

FIG. 4 is a flowchart showing a substrate process according to anembodiment of the present disclosure.

FIG. 5 is an explanatory view of a substrate on which a groove (trench)to be processed in a substrate process according to an embodiment of thepresent disclosure is formed.

FIG. 6 is a view showing height positions of probes installed inside aplasma generation space and a substrate process space in a verificationexample.

FIG. 7 is a view showing installation positions of probes at respectiveheight positions in the verification example.

FIG. 8 is a view showing the measurement values of plasma densitydistributions at the height positions in the verification example.

FIG. 9 is a view showing the measurement results of plasma densitydistributions at the height positions in the verification example.

DETAILED DESCRIPTION First Embodiment of the Present Disclosure (1)Configuration of Substrate Processing Apparatus

A substrate processing apparatus according to a first embodiment of thepresent disclosure will be described below with reference to FIGS. 1 and2. The substrate processing apparatus according to the presentembodiment is configured to mainly perform an oxidizing process on afilm formed on a surface of a substrate.

(Process Chamber)

A processing device 100 includes a process furnace 202 forplasma-processing a wafer 200. A process container 203 constituting aprocess chamber 201 is installed in the process furnace 202. The processcontainer 203 includes a dome-shaped upper container 210 which is afirst container and a bowl-shaped lower container 211 which is a secondcontainer. The lower container 211 is covered with the upper container210 so that the process chamber 201 is formed. The upper container 210is made of, for example, a nonmetallic material such as aluminum oxide(Al₂O₃) or quartz (SiO₂), and the lower container 211 is made of, forexample, aluminum (Al).

In addition, a gate valve 244 is installed in a lower side wall of thelower container 211. When the gate valve 244 is opened, the wafer 200can be loaded into or unloaded from the process chamber 201 via aloading/unloading port 245 using a transfer mechanism (not shown). Thegate valve 244, when being closed, serves as a partitioning valve forsecuring airtightness inside the process chamber 201.

The process chamber 201 includes a plasma generation space 201 a aroundwhich a resonance coil 212 is installed, and a substrate process space201 b which is in communication with the plasma generation space 201 aand which processes the wafer 200 received therein. The plasmageneration space 201 a is a space in which plasma is generated. Theplasma generation space 201 a refers to a space defined above a lowerend of the resonance coil 212 and below an upper end of the resonancecoil 212 inside the process chamber 201. On the other hand, thesubstrate process space 201 b is a space in which the substrate isprocessed using plasma. The substrate process space 201 b refers to aspace defined below the lower end of the resonance coil 212. In thepresent embodiment, the diameters of the plasma generation space 201 aand the substrate process space 201 b in the horizontal direction areset to be substantially equal to each other.

(Susceptor)

A susceptor (substrate mounting table) 217 serving as a substratemounting part for mounting the wafer 200 thereon is disposed at thebottom center of the process chamber 201. The susceptor 217 is made of,for example, a nonmetallic material such as aluminum nitride (AlN),ceramics, quartz or the like, and is configured to reduce metalcontamination on a film or the like formed on the wafer 200.

A heater 217 b as a heating mechanism is integrally embedded in thesusceptor 217. The heater 217 b is configured to, when supplied withelectric power, heat the surface of the wafer 200, for example, from 25degrees C. to 750 degrees C.

The susceptor 217 is electrically insulated from the lower container211. An impedance adjustment electrode 217 c is installed inside thesusceptor 217 in order to further improve the uniformity of the densityof the plasma generated on the wafer 200 which is mounted on thesusceptor 217. The impedance adjustment electrode 217 c is grounded viaan impedance varying mechanism 275 as an impedance adjustment part. Theimpedance varying mechanism 275 is composed of a coil and a variablecapacitor. The impedance varying mechanism 275 is configured to vary theimpedance within a range from about 0Ω to a parasitic impedance value ofthe process chamber 201 by controlling inductance and resistance of thecoil and a capacitance value of the variable capacitor. As a result, thepotential (bias voltage) of the wafer 200 can be controlled via theimpedance adjustment electrode 217 c and the susceptor 217. In thepresent embodiment, the uniformity of the density of the plasmagenerated on the wafer 200 can be improved as will be described later.Therefore, if the uniformity of the density of the plasma falls within adesired range, the bias voltage control using the impedance adjustmentelectrode 217 c is not performed. Further, when the bias voltage controlis not performed, the impedance adjustment electrode 217 c may not beinstalled in the susceptor 217. However, the bias voltage control may beperformed for the purpose of further improving the uniformity.

A susceptor elevating mechanism 268 equipped with a driving mechanismfor raising and lowering the susceptor 217 is installed in the susceptor217. In addition, through-holes 217 a are formed in the susceptor 217,and wafer lifting pins 266 are installed on the bottom surface of thelower container 211. The through-holes 217 a and the wafer lifting pins266 are provided at at least three locations at respective positionsfacing each other. When the susceptor 217 is lowered by the susceptorelevating mechanism 268, the wafer lifting pins 266 are configured topenetrate the through-holes 217 a in a state in which the wafer liftingpins 266 do not make contact with the susceptor 217. A substratemounting part according to the present embodiment is mainly configuredby the susceptor 217, the heater 217 b and the electrode 217 c.

(Gas Supply Part)

A gas supply head 236 is installed above the process chamber 201, namelyabove the upper portion of the upper container 210. The gas supply head236 includes a cap-like lid 233, a gas inlet port 234, a buffer chamber237, an opening 238, an additional shielding plate 240 and a gas outletport 239. The gas supply head 236 is configured to supply a reaction gasinto the process chamber 201. The buffer chamber 237 functions as adispersion space for dispersing the reaction gas introduced from the gasinlet port 234.

A downstream end of an oxygen-containing gas supply pipe 232 a forsupplying an oxygen (O₂) gas as an oxygen-containing gas, a downstreamend of a hydrogen-containing gas supply pipe 232 b for supplying ahydrogen (H₂) gas as a hydrogen-containing gas and a downstream end ofan inert gas supply pipe 232 c for supplying an argon (Ar) gas as aninert gas are connected to the gas inlet port 234 while being joinedwith each other. In the oxygen-containing gas supply pipe 232 a, an O₂gas supply source 250 a, a mass flow controller (MFC) 252 a as a flowrate control device and a valve 253 a as an opening/closing valve areinstalled sequentially from the upstream side. In thehydrogen-containing gas supply pipe 232 b, an H₂ gas supply source 250b, an MFC 252 b and a valve 253 b are installed sequentially from theupstream side. In the inert gas supply pipe 232 c, an Ar gas supplysource 250 c, an MFC 252 c and a valve 253 c are installed sequentiallyfrom the upstream side. A valve 243 a is installed at the downstreamside of the joint point of the oxygen-containing gas supply pipe 232 a,the hydrogen-containing gas supply pipe 232 b and the inert gas supplypipe 232 c. The valve 243 a is connected to an upstream end of the gasinlet port 234. By opening and closing the valves 253 a, 253 b, 253 cand 243 a, a processing gas such as the oxygen-containing gas, thehydrogen-containing gas, the inert gas or the like can be supplied intothe process chamber 201 via the gas supply pipes 232 a, 232 b and 232 cwhile controlling the flow rates of the respective gases by the MFCs 252a, 252 b and 252 c.

A gas supply part (gas supply system) according to the presentembodiment is mainly constituted by the gas supply head 236 (the lid233, the gas inlet port 234, the buffer chamber 237, the opening 238,the additional shielding plate 240 and the gas outlet port 239), theoxygen-containing gas supply pipe 232 a, the hydrogen-containing gassupply pipe 232 b, the inert gas supply pipe 232 c, the MFCs 252 a, 252b and 252 c, and the valves 253 a, 253 b, 253 c and 243 a.

Further, an oxygen-containing gas supply system according to the presentembodiment is constituted by the gas supply head 236, theoxygen-containing gas supply pipe 232 a, the MFC 252 a, and the valves253 a and 243 a. Moreover, a hydrogen gas supply system according to thepresent embodiment is constituted by the gas supply head 236, thehydrogen-containing gas supply pipe 232 b, the MFC 252 b, and the valves253 b and 243 a. In addition, an inert gas supply system according tothe present embodiment is constituted by the gas supply head 236, theinert gas supply pipe 232 c, the MFC 252 c, and the valves 253 c and 243a.

The substrate processing apparatus according to the present embodimentis configured to perform an oxidizing process by supplying an O₂ gas asan oxygen-containing gas from the oxygen-containing gas supply system.However, a nitrogen-containing gas supply system for supplying anitrogen-containing gas into the process chamber 201 may be installed inplace of the oxygen-containing gas supply system. According to thesubstrate processing apparatus configured as described above, anitriding process can be performed on the substrate instead of theoxidizing process. In this case, for example, an N₂ gas supply source asthe nitrogen-containing gas supply source may be installed instead ofthe O₂ gas supply source 250 a, and the oxygen-containing gas supplypipe 232 a may be configured as a nitrogen-containing gas supply pipe.

(Exhaust Part)

A gas exhaust port 235 for exhausting the reaction gas outward from theinterior of the process chamber 201 is formed in the side wall of thelower container 211. An upstream end of a gas exhaust pipe 231 isconnected to the gas exhaust port 235. In the gas exhaust pipe 231, anAPC (Auto Pressure Controller) 242 as a pressure regulator (pressureregulating part), a valve 243 b as an opening/closing valve and a vacuumpump 246 as a vacuum exhaust device are installed sequentially from theupstream side. An exhaust part according to the present embodiment ismainly constituted by the gas exhaust port 235, the gas exhaust pipe231, the APC 242 and the valve 243 b. The vacuum pump 246 may beincluded in the exhaust part.

(Plasma Generation Part)

The resonance coil 212 having a helical shape as a first electrode isinstalled so as to surround the process chamber 201 in an outerperipheral portion of the process chamber 201, namely outside the sidewall of the upper container 210. A RF sensor 272, a high-frequency powersupply 273 and a matcher 274 for matching an impedance and an outputfrequency of the high-frequency power supply 273 are connected to theresonance coil 212.

The high-frequency power supply 273 is configured to supply ahigh-frequency power (RF power) to the resonance coil 212. The RF sensor272 is installed at the output side of the high-frequency power supply273 and is configured to monitor information on a traveling wave or areflected wave of the supplied high-frequency power. The reflected wavepower monitored by the RF sensor 272 is inputted to the matcher 274.Based on the information on the reflected wave inputted from the RFsensor 272, the matcher 274 is configured to control the impedance ofthe high-frequency power supply 273 and a frequency of the outputtedhigh-frequency power so that the reflected wave is minimized.

The high-frequency power supply 273 includes a power supply controlmeans (control circuit) which is provided with a high-frequencyoscillation circuit and a preamplifier for defining an oscillationfrequency and output power, and an amplifier (output circuit) foramplifying electric power to predetermined output power. The powersupply control means controls the amplifier based on output conditionsrelating to the frequency and power set in advance through an operationpanel. The amplifier supplies constant high-frequency power to theresonance coil 212 via a transmission line.

In order for the resonance coil 212 to form a standing wave of apredetermined wavelength, a winding diameter, a winding pitch and thenumber of turns of the resonance coil 212 are set so that the resonancecoil 212 can resonate at a certain wavelength. That is to say, anelectrical length of the resonance coil 212 is set to a lengthcorresponding to an integral multiple (1 time, 2 times, or . . . ) ofone wavelength at a predetermined frequency of the high-frequency powersupplied from the high-frequency power supply 273.

Specifically, in view of the applied electric power, the generatedmagnetic field strength, the applied external form of the apparatus andthe like, the resonance coil 212 is configured to have an effectivesectional area of 50 to 300 mm² and a coil diameter of 200 to 500 mm andto be wound around the outer periphery side of a room in which theplasma generation space 201 a is formed by about 2 to 60 turns, so thatthe resonance coil 212 can generate a magnetic field of about 0.01 to 10gauss at, for example, the frequency of 800 kHz to 50 MHz and thehigh-frequency power of 0.5 to 5 kW.

As an embodiment, for example, when the frequency is 13.56 MHz, thelength of one wavelength is about 22 meters. When the frequency is 27.12MHz, the length of one wavelength is about 11 meters. The electricallength of the resonance coil 212 is set to become these lengths of onewavelength (1 time). In the present embodiment, the frequency of thehigh-frequency power is set to 27.12 MHz and the electrical length ofthe resonance coil 212 is set to the length of one wavelength (about 11meters). The winding pitch of the resonance coil 212 is set so that theresonance coil 212 is wound at equal intervals, for example, atintervals of 24.5 mm. Further, the winding diameter of the resonancecoil 212 is set to be larger than the diameter of the wafer 200. In thepresent embodiment, the diameter of the wafer 200 is 300 mm, and thewinding diameter of the resonance coil 212 is 500 mm which is largerthan the diameter of the wafer 200.

A copper pipe, a thin copper plate, an aluminum pipe, a thin aluminumplate, a material obtained by vapor-depositing copper or aluminum on apolymer belt, or the like is used as a material constituting theresonance coil 212. The resonance coil 212 is formed in a flat plateshape with an insulating material, and is supported by a plurality ofsupports (not shown) installed vertically on an upper end face of a baseplate 248.

Both ends of the resonance coil 212 are electrically grounded. At leastone of the both ends of the resonance coil 212 is grounded via a movabletap 213 so as to finely adjust the electrical length of the resonancecoil 212 at the time of initially installing the device or at the timeof changing process conditions. Reference numeral 214 in FIG. 1 denotesa fixed ground which is installed at the other side of the resonancecoil 212. The position of the movable tap 213 is adjusted so that theresonance characteristic of the resonance coil 212 becomes substantiallyequal to that of the high-frequency power supply 273. In order to finelyadjust the impedance of the resonance coil 212 at the time of theinitial installation of the device or at the time of the change of theprocess conditions, a power feeding part is configured by providing themovable tap 215 between the grounded ends of the resonance coil 212.Since the resonance coil 212 includes the variable ground part and thevariable power feeding part, it is possible to adjust the resonancefrequency and the load impedance of the process chamber 201 in a moresimplified manner, which will be described later.

Further, a waveform adjustment circuit (not shown) including a coil anda shield is inserted to one end (or the other end or both ends) of theresonance coil 212 so that a phase current and an antiphase currentflows symmetrically with respect to the electric midpoint of theresonance coil 212. The waveform adjustment circuit is configured as anopened circuit by setting the end portion of the resonance coil 212 tostay in an electrical disconnection state or setting the end portion ofthe resonance coil 212 to stay in an electrical equivalent state. Theend portion of the resonance coil 212 may be ungrounded by a chokeseries resistor and may be DC-connected to a fixed reference potential.

A shielding plate 223 is installed to shield an electric field outsidethe resonance coil 212 and to form a capacitance component (C component)necessary for constructing the resonance circuit between the shieldingplate 223 and the resonance coil 212. In general, the shielding plate223 is formed in a cylindrical shape with a conductive material such asan aluminum alloy or the like. The shielding plate 223 is disposed at adistance of about 5 to 150 mm from the outer periphery of the resonancecoil 212. Normally, the shielding plate 223 is grounded so that thepotential thereof becomes equal to that of both ends of the resonancecoil 212. However, in order to accurately set the resonance number ofthe resonance coil 212, one end or both ends of the shielding plate 223is configured so that a tap position can be adjusted. Alternatively, inorder to accurately set the resonance number, a trimming capacitance maybe inserted between the resonance coil 212 and the shielding plate 223.

A plasma generation part according to the present embodiment is mainlyconstituted by the resonance coil 212, the RF sensor 272 and the matcher274. The high-frequency power supply 273 may be included in the plasmageneration part.

A plasma generation principle of the device according to the presentembodiment and properties of the generated plasma will now be describedwith reference to FIG. 2. A plasma generation circuit constituted by theresonance coil 212 is composed of a parallel resonance circuit of RLC.When the wavelength of the high-frequency power supplied from thehigh-frequency power supply 273 is equal to the electrical length of theresonance coil 212, the resonance condition of the resonance coil 212 issuch that a reactance component produced by a capacitive component andan inductive component of the resonance coil 212 is canceled out andbecomes a pure resistance. However, in the plasma generation circuitdescribed above, when plasma is generated, the actual resonancefrequency fluctuates slightly due to a fluctuation in capacitivecoupling between a voltage portion of the resonance coil 212 and theplasma, a fluctuation in inductive coupling between the plasmageneration space 201 a and the plasma, an excited state of the plasma,and the like.

Thus, in the present embodiment, the deviation of resonance in theresonance coil 212 at the time of plasma generation is compensated atthe side of the power supply. To do this, the reflected wave power fromthe resonance coil 212 at the time of plasma generation is detected bythe RF sensor 272. The matcher 274 has a function of correcting theoutput of the high-frequency power supply 273 based on the reflectedwave power thus detected.

Specifically, based on the reflected wave power from the resonance coil212 at the time of plasma generation, which is detected by the RF sensor272, the matcher 274 increases or decreases the impedance or the outputfrequency of the high-frequency power supply 273 so as to minimize thereflected wave power. In the case of controlling the impedance, thematcher 274 is constituted by a variable capacitor control circuit forcorrecting a preset impedance. In the case of controlling the frequency,the matcher 274 is constituted by a frequency control circuit forcorrecting a preset oscillation frequency of the high-frequency powersupply 273. The high-frequency power supply 273 and the matcher 274 maybe configured as a single unit.

With such a configuration, in the resonance coil 212 according to thepresent embodiment, as shown in FIG. 2, the high frequency poweraccording to the actual resonance frequency of the resonance coilincluding plasma is supplied (or, the high-frequency power is suppliedso as to match the impedance of the resonance coil including plasma).This forms a standing wave in a state where the phase voltage and theantiphase voltage are always canceled out. When the electrical length ofthe resonance coil 212 is equal to the wavelength of the high-frequencypower, the highest phase current is generated at the electrical midpointof the coil, an electrical upper end of the coil, and an electricallower end of the coil (at a node where the voltage is zero). Therefore,a donut-like induction plasma, which has almost no capacitive couplingwith the wall of the process chamber or the susceptor 217 and which hasextremely low electric potential, is formed in the vicinity of theelectrical midpoint, the electrical upper end, and the electrical lowerend of the coil.

(Control Part)

A controller 221 as the control part is configured to control the APC242, the valve 243 b and the vacuum pump 246 through a signal line A,control the susceptor elevating mechanism 268 through a signal line B,control the heater power adjustment mechanism 276 and the impedancevarying mechanism 275 through a signal line C, control the gate valve244 through a signal line D, control the RF sensor 272, thehigh-frequency power supply 273 and the matcher 274 through a signalline E, and control the MFCs 252 a to 252 c and the valves 253 a to 253c and 243 a through a signal line F.

As shown in FIG. 3, the controller 221 used as the control part (controlmeans) is configured as a computer including a CPU (Central ProcessingUnit) 221 a, a RAM (Random Access Memory) 221 b, a memory device 221 cand an I/O port 221 d. The RAM 221 b, the memory device 221 c and theI/O port 221 d are configured to exchange data with the CPU 221 a via aninternal bus 221 e. An input/output device 222 composed of, for example,a touch panel, a display or the like is connected to the controller 221.

The memory device 221 c is composed of, for example, a flash memory, anHDD (Hard Disk Drive) or the like. In the memory device 221 c, a controlprogram for controlling the operation of the substrate processingapparatus, a process recipe in which sequences and conditions of thesubstrate process to be described later are written, and the like arestored in a readable manner. The process recipe functions as a programto cause the controller 221 to execute respective sequences in thesubstrate process to be described later so as to obtain a predeterminedresult. Hereinafter, the process recipe and the control program will begenerally and simply referred to as a “program.” When the term “program”is used herein, it may indicate a case of including only the processrecipe, a case of including only the control program, or a case ofincluding both the process recipe and the control program. The RAM 221 bis configured as a memory area (work area) in which a program or dataread by the CPU 221 a is temporarily stored.

The I/O port 221 d is connected to the MFCs 252 a to 252 c, the valves253 a to 253 c, 243 a and 243 b, the gate valve 244, the APC 242, thevacuum pump 246, the RF sensor 272, the high-frequency power supply 273,the matcher 274, the susceptor elevating mechanism 268, the impedancevarying mechanism 275, the heater power adjustment mechanism 276, andthe like.

The CPU 221 a is configured to read the control program from the memorydevice 221 c and execute the same. The CPU 221 a is also configured toread the process recipe from the memory device 221 c according to anoperation command inputted from the input/output device 222. The CPU 221a is configured to, according to the contents of the process recipe thusread, control the operation of adjusting the opening degree of the APC242, the opening/closing operation of the valve 243 b and thestartup/stoppage of the vacuum pump 246 through the I/O port 221 d andthe signal line A, control the elevating operation of the susceptorelevating mechanism 268 through the signal line B, control the powersupply amount adjustment operation (temperature adjustment operation) ofthe heater 217 b performed by the heater power adjustment mechanism 276and the impedance value adjustment operation performed by the impedancevarying mechanism 275 through the signal line C, control theopening/closing operation of the gate valve 244 through the signal lineD, control the operations of the RF sensor 272, the matcher 274 and thehigh-frequency power supply 273 through the signal line E, and controlthe flow rate adjustment operation of various gases performed by theMFCs 252 a to 252 c and the opening/closing operation of the valves 253a to 253 c and 243 a through the signal line F.

The controller 221 may be configured by installing, on a computer, theaforementioned program stored in an external memory device 224 (forexample, a magnetic tape, a magnetic disk such as a flexible disk, ahard disk or the like, an optical disk such as a CD, a DVD or the like,a magneto-optical disk such as an MO or the like, or a semiconductormemory such as a USB memory, a memory card or the like). The memorydevice 221 c or the external memory device 224 is configured as anon-transitory computer-readable recording medium. Hereinafter, thememory device 221 c and the external memory device 224 will be generallyand simply referred to as a “recording medium.” When the term “recordingmedium” is used herein, it may indicate a case of including only thememory device 221 c, a case of including only the external memory device224, or a case of including both the memory device 221 c and theexternal memory device 224. The provision of the program to the computermay be performed using a communication means such as the Internet or adedicated line without using the external memory device 224.

(2) Substrate Process

Next, the substrate process according to the present embodiment will bedescribed mainly with reference to FIG. 4. FIG. 4 is a flowchart showingthe substrate process according to the present embodiment. As one ofvarious processes of manufacturing a semiconductor device such as aflash memory or the like, the substrate process according to the presentembodiment is executed by the above-described processing device 100. Inthe following description, the operations of the respective partsconstituting the processing device 100 are controlled by the controller221.

For example, as shown in FIG. 5, a trench 301 having at least a siliconlayer formed thereon and having an uneven portion with a high aspectratio is formed in advance on the surface of the wafer 200 processed inthe substrate process according to the present embodiment. In thepresent embodiment, the silicon layer exposed on an inner wall of thetrench 301 is subjected to an oxidizing process as a plasma-basedprocess. The trench 301 is formed by, for example, forming a mask layer302 having a predetermined pattern on the wafer 200 and subsequentlyetching the surface of the wafer 200 to a predetermined depth.

(Substrate Loading Step S110)

First, the wafer 200 is loaded into the process chamber 201. Morespecifically, the susceptor elevating mechanism 268 lowers the susceptor217 to a wafer transfer position at which the wafer 200 is transferred,thereby allowing the wafer lifting pins 266 to pass through therespective through-holes 217 a of the susceptor 217. As a result, thewafer lifting pins 266 remains protruded by a predetermined height fromthe surface of the susceptor 217.

Subsequently, the gate valve 244 is opened, and the wafer 200 is loadedinto the process chamber 201 from a vacuum transfer chamber adjacent tothe process chamber 201 by using a wafer transfer mechanism (not shown).The loaded wafer 200 is supported on the wafer lifting pins 266protruding from the surface of the susceptor 217 in a horizontalposture. After loading the wafer 200 into the process chamber 201, thewafer transfer mechanism is withdrawn outward of the process chamber201. The gate valve 244 is closed to hermetically seal the interior ofthe process chamber 201. Then, the susceptor elevating mechanism 268raises the susceptor 217 so that the wafer 200 is supported on the uppersurface of the susceptor 217.

(Temperature Increasing/Vacuum Exhaust Step S120)

Subsequently, the temperature of the wafer 200 loaded into the processchamber 201 is increased. The heater 217 b is heated in advance. Byholding the wafer 200 on the susceptor 217 in which the heater 217 b isembedded, the wafer 200 is heated to a predetermined temperature fallingwithin a range of, for example, 150 to 750 degrees C. In the presentembodiment, the wafer W is heated at a temperature of 600 degrees C.While increasing the temperature of the wafer 200, the interior of theprocess chamber 201 is evacuated by the vacuum pump 246 via the gasexhaust pipe 231, thereby setting an internal pressure of the processchamber 201 to a predetermined value. The vacuum pump 246 is operated atleast until a substrate unloading step S160 described later iscompleted.

(Reaction Gas Supply Step S130)

Subsequently, an O₂ gas as the oxygen-containing gas and an H₂ gas asthe hydrogen-containing gas, which are reaction gases, are started to besupplied. Specifically, the valves 253 a and 253 b are opened, and thesupply of the O₂ gas and the H₂ gas into the process chamber 201 isstarted while controlling flow rates thereof with the MFCs 252 a and 252b. At this time, the flow rate of the O₂ gas is set to a predeterminedvalue falling within a range of, for example, 20 to 2,000 sccm,specifically 20 to 1,000 sccm. The flow rate of the H₂ gas is set to apredetermined value falling within a range of, for example, 20 to 1,000sccm, specifically 20 to 500 sccm. As a more specific example, the totalflow rate of the O₂ gas and the H₂ gas may be set to 1,000 sccm, and aflow rate ratio of the O₂ gas to the H₂ gas may be set to O₂/H₂≥950/50.In addition, the exhaust of the interior of the process chamber 201 iscontrolled by adjusting the opening degree of the APC 242 so that theinternal pressure of the process chamber 201 becomes a predeterminedpressure falling within a range of, for example, 1 to 250 Pa,specifically 50 to 200 Pa, and more specifically about 150 Pa. Whileappropriately exhausting the interior of the process chamber 201 asdescribed above, the supply of the O₂ gas and the H₂ gas is continueduntil the end of a plasma processing step S140 described later.

(Plasma Processing Step S140)

After the internal pressure of the process chamber 201 is stabilized,the high-frequency power begins to be applied to the resonance coil 212from the high-frequency power supply 273 via the RF sensor 272. In thepresent embodiment, the high-frequency power of 27.12 MHz is suppliedfrom the high-frequency power supply 273 to the resonance coil 212. Thehigh-frequency power supplied to the resonance coil 212 is apredetermined electric power falling within a range of, for example, 100to 5,000 W, specifically 100 to 3,500 W, and more specifically about3,500 W. When the electric power is lower than 100 W, it is difficult tostably generate the plasma discharge.

As a result, a high-frequency electric field is formed inside the plasmageneration space 201 a to which the O₂ gas and the H₂ gas are supplied.By virtue of this electric field, donut-like induction plasma having ahighest plasma density is excited at a height position corresponding tothe electrical midpoint of the resonance coil 212 inside the plasmageneration space. Each of the plasmarized O₂ gas and the plasmarized H₂gas is dissociated, whereby reactive species such as oxygen radicalscontaining oxygen (oxygen active species) or oxygen ions, hydrogenradicals containing hydrogen (hydrogen active species) or hydrogen ions,and the like are generated.

As described above, when the electrical length of the resonance coil 212is equal to the wavelength of the high-frequency power, donut-likeinduction plasma having an extremely low electrical potential is excitedinside the plasma generation space 201 a in the vicinity of theelectrical midpoint of the resonance coil 212 while making almost nocapacitive coupling with the wall of the process chamber and thesubstrate mounting table. Since the plasma having an extremely lowelectrical potential is generated, it is possible to prevent a sheathfrom being generated on the wall of the plasma generation space 201 a oron the susceptor 217. Therefore, in the present embodiment, ions in theplasma are not accelerated.

Radicals generated by induction plasma and ions kept in anon-accelerated state are uniformly supplied into the trench 301 of thewafer 200 held on the susceptor 217 inside the substrate process space201 b. The supplied radicals and ions uniformly react with side walls301 a and 301 b to modify the silicon layer formed on the surface into asilicon oxide layer having good step coverage.

Furthermore, since the acceleration of ions is prevented, it is possibleto suppress damage of the wafer 200 due to accelerated ions.Furthermore, the sputtering action on the peripheral wall of the plasmageneration space can be suppressed so that peripheral wall of the plasmageneration space 201 a does not undergo damage.

Moreover, the reflected wave power caused by the impedance mismatchgenerated by the resonance coil 212 is compensated at the side of thehigh-frequency power supply 273 by the matcher 274 attached to thehigh-frequency power supply 273 so that a reduction in effective loadpower is complemented. Thus, it is possible to reliably supply aninitial level of high-frequency power to the resonance coil 212 at alltimes and to stabilize the plasma. Accordingly, the wafer 200 held inthe substrate process space 201 b can be uniformly processed at aconstant rate.

In the case of the present embodiment, the susceptor elevating mechanism268 is controlled so that the vertical position of the wafer 200 in theplasma processing step is set at a distance of 38 mm or more downwardaway from the lower end of the resonance coil 212. By setting theposition of the wafer 200 in the plasma processing step as describedabove, it is possible for the wafer 200 to be spaced apart by asufficient distance from the donut-like induction plasma formed insidethe plasma generation space 201 a as described later. Therefore, thedensity of the plasma generated on the surface of the wafer 200 becomesuniform in the plane direction (horizontal direction), which makes itpossible to uniformly perform the plasma process in the plane of thewafer 200. That is to say, in the plane of the wafer 200, the uniformityof the thickness of the layer (silicon oxide layer in the presentembodiment) formed by the plasma process can be improved.

If the case where the winding diameter of the resonance coil 212 islarger than the diameter of the wafer 200 as in the present embodiment(for example, if the winding diameter of the resonance coil 212 is 500mm whereas the diameter of the wafer 200 is 300 mm), no donut-likeinduction plasma is generated directly above the wafer 200. Thus, thedeviation of the density of the plasma generated above the surface ofthe wafer 200 is lessened. This makes it possible to improve theuniformity of the plasma process in the plane of the wafer 200.

In the present embodiment, so as to support the wafer 200 on the uppersurface of the susceptor 217, it is preferable that the susceptor 217 israised so that the vertical position of the wafer 200 is higher than thetips of the wafer lifting pins 266. If the vertical position of thewafer 200 in the plasma processing step is too spaced apart downwardfrom the lower end of the resonance coil 212, the radicals and ionsgenerated by the plasma may be deactivated. As a result, a process ratemay be below a practical value. Therefore, the vertical position of thewafer 200 in the plasma processing step needs to be at least such aposition that the radicals and ions generated by the plasma are notdeactivated. According to the verification conducted by the presentinventors, it has been confirmed that, in the present embodiment, if thevertical position of the wafer 200 falls within a range of 138 mmdownward from the lower end of the resonance coil 212, the uniformity ofthe plasma process in the wafer plane can be sufficiently secured whilemaintaining a practical process rate.

Thereafter, when a predetermined period of process time, for example, 10to 300 seconds elapses, the output of the electric power from thehigh-frequency power supply 273 is stopped so that the plasma dischargeinside the process chamber 201 is stopped. In addition, the valves 253 aand 253 b are closed to stop the supply of the O₂ gas and the H₂ gasinto the process chamber 201. In this way, the plasma processing stepS140 is completed.

(Vacuum Exhaust Step S150)

After the supply of the O₂ gas and the H₂ gas is stopped, the interiorof the process chamber 201 is evacuated via the gas exhaust pipe 231. Asa result, the O₂ gas and the H₂ gas remaining in the process chamber201, an exhaust gas generated by the reaction of these gases, and thelike are exhausted outward of the process chamber 201. Thereafter, theopening degree of the APC 242 is adjusted such that the internalpressure of the process chamber 201 is regulated to be the same pressure(for example, 100 Pa) as an internal pressure of a vacuum transferchamber (in a destination (not shown) to which the wafer 200 is to beunloaded) provided adjacent to the process chamber 201.

(Substrate Unloading Step S160)

When the internal pressure of the process chamber 201 reaches apredetermined pressure, the susceptor 217 is lowered to the wafertransfer position so that the wafer 200 is supported on the waferlifting pins 266. Then, the gate valve 244 is opened and the wafer 200is unloaded from the process chamber 201 by a wafer transfer mechanism.In this way, the substrate process according to the present embodimentis ended.

In the present embodiment, there has been described the example in whichthe O₂ gas and the H₂ gas are plasma-excited to perform the plasmaprocess on the substrate. However, the present disclosure is not limitedto this example. For example, instead of the O₂ gas, an N₂ gas may besupplied into the process chamber 201, and the N₂ gas and the H₂ gas maybe plasma-excited to perform a nitriding process on the substrate. Inthis case, it may be possible to use the processing device 100 includingthe above-described nitrogen-containing gas supply system in place ofthe above-described oxygen-containing gas supply system.

(Effects of the Present Embodiment)

The effects of the present embodiment will be described based on theresults of verification conducted by the present inventors. In thisverification, probes for measuring the electron density at predeterminedpositions inside the plasma generation space 201 a and the substrateprocess space 201 b in the substrate processing apparatus according tothe present embodiment were installed at the predetermined positions tomeasure the distribution of the density of plasma or reactive speciessuch as radicals or ions (hereinafter simply referred to as “plasmadensity”) inside the plasma generation space 201 a and the substrateprocess space 201 b. Plasma generation conditions at the time of thismeasurement are as follows. At the time of measurement, a bare siliconwafer was mounted on the susceptor 217.

-   -   Flow rate of supplied gas: O₂ gas=950 sccm, H₂ gas=50 sccm    -   Internal pressure of process chamber: 150 Pa    -   RF frequency: 27.12 MHz    -   RF power: 3,500 W

FIG. 6 is a view showing height positions of the probes installed insidethe plasma generation space 201 a and the substrate process space 201 b.In this verification, five probes were installed in each of the heightpositions (a) to (d) in the horizontal direction. That is to say, inthis verification, the probes were installed at 20 locations in totaland the distribution of the plasma density was measured.

The height position (b) is a lower end position of the resonance coil212. Hereinafter, the height positions (a), (c) and (d) will bedescribed using the height position (b) as a reference position (0 mm).The height position (a) is an intermediate position between the upperend and the lower end of the resonance coil 212, which is spaced apartby a distance of 100 mm upward from the lower end of the resonance coil212. The height position (a) is a position near the electrical midpointof the resonance coil 212 and at which the donut-like induction plasmahaving a highest plasma density is excited. The height position (c) is aposition spaced apart by a distance of 38 mm downward from the lower endof the resonance coil 212. The height position (d) is a position spacedapart by a distance of 88 mm downward from the lower end of theresonance coil 212. In addition, the bare silicon wafer is mounted on aposition spaced further apart by a distance of 50 mm downward from theheight position (d).

FIG. 7 is a view showing the installation positions of the probes ateach of the height positions (a) to (d). The installation positions ofthe probes at the respective height positions are all the same. M, L1,L2, R1 and R2 in FIG. 7 indicate tip positions of the probes(measurement positions of the plasma density), respectively. M is aposition corresponding to the center position of the wafer to bemounted. L1 is a position defined by moving the probe by 30 degrees tothe left side from M. L2 is a position defined by moving the probe by 60degrees to the left side from M, which corresponds to one outer edgeportion of the wafer. R1 is a position defined by moving the probe by 30degrees to the right side from M. R2 is a position defined by moving theprobe by 60 degrees to the right side from M, which corresponds toanother outer edge portion of the wafer. That is to say, the plasmadensity distribution in a wafer plane direction (horizontal direction)was measured by measuring the plasma density at M, L1, L2, R1 and R2.

FIG. 8 is a table showing the measurement results of the plasma densitydistributions at the height positions (a) to (d) under the plasmageneration conditions described above. Further, FIG. 9 is a viewgraphically showing the values of the results shown in FIG. 8. In FIG.9, the plasma density is represented by the number of electrons(electron density) per 1 cm³. At the height position (a), donut-likeinduction plasma having a highest plasma density is excited. Therefore,the plasma density grows high in the vicinity of the resonance coil 212(i.e., in the outer edge portion of the wafer), and the plasma densitygrows relatively low in the central portion of the resonance coil 212 inthe winding direction.

In the resonance coil 212 according to the present embodiment, thedonut-like induction plasma is excited even at the height position (b)which corresponds to the lower end portion of the resonance coil 212.Therefore, even at the height position (b), the plasma density growshigh in the vicinity of the resonance coil 212 (i.e., in the outer edgeportion of the wafer), and the plasma density tends to be relatively lowin the central portion of the resonance coil 212 in the windingdirection.

As described above, a deviation in the plasma density in the wafer planedirection is generated between the height positions (a) and (b), namelybetween the lower end portion of the resonance coil 212 and a portionabove the lower end portion (that is to say, a deviation in the densityof reactive species reacting with a target film formed on the wafersurface is generated). It can be noted that it is difficult to performthe plasma process on the substrate while maintaining the wafer in-planeuniformity of the plasma process at these height positions.

On the other hand, at the height positions (c) and (d), there is almostno deviation in the plasma density distribution in the wafer planedirection. That is to say, in view of the plasma density distribution atthe height positions (c) and (d), it is presumed that no deviation issubstantially generated in the plasma density in the wafer planedirection at at least a position below the height position (c).Therefore, in order to secure the wafer in-plane uniformity in theplasma process using the substrate processing apparatus according to thepresent embodiment, the wafer needs to be processed at the heightposition (c), namely the height position spaced apart by a distance of38 mm or more downward from the lower end of the resonance coil 212.

As described above, when the position of the wafer in the plasmaprocessing step is too far downward from the lower end of the resonancecoil 212, radicals and ions generated by the plasma excitation may bedeactivated. Because of this, the processing rate may be lower than apractical value. Therefore, the vertical position of the wafer 200 inthe plasma processing step needs to be at least such a position thatradicals and ions generated by the plasma-excitation are notdeactivated. According to another verification using the substrateprocessing apparatus according to the present embodiment, it can benoted that, similar to the height positions (c) and (d), a good plasmadensity distribution enough to realize a practical processing rate isobtained even at the height position of the bare wafer mounted on thesusceptor 217, namely the height position spaced apart by a distance of138 mm downward from the lower end of the resonance coil 212.Accordingly, in the substrate processing apparatus according to thepresent embodiment, by processing the wafer at least at a positionspaced apart by a distance ranging 38 to 138 mm downward from the lowerend of the resonance coil 212, it is possible to realize a practicalprocessing rate while maintaining the wafer in-plane uniformity in theplasma process.

As another verification, the present inventors also verified a casewhere the power value of the supplied RF power is changed in a practicalrange (for example, 3,000 W or 2,500 W) with respect to the conditionsunder which the aforementioned verification has been performed. In thiscase, as the power value increases, the plasma density may increase overthe entire plane direction of the wafer 200, and a deviation in theplasma density in the plane direction of the wafer may also be changed.On the other hand, it was confirmed that, in the height range describedabove, there is no significant change in the tendency of deviation ofthe plasma density in the plane direction of the wafer. That is to say,in the above-described height range, it is presumed that even in thecase of changing the power value of the supplied RF power, it ispossible to secure the wafer in-plane uniformity in the plasma process.

Similarly, as a further verification, the present inventors haveconfirmed that when the internal pressure of the process chamber ischanged (for example, 50 Pa) in a practical range with respect to theconditions under which the above-described verification has beenperformed, there is no significant change in the tendency of deviationof the plasma density in the plane direction of the wafer, while theplasma density is changed over the entire plane direction of the wafer(for example, the plasma density increases when the internal pressure is50 Pa rather than 150 Pa). That is to say, in the above-described heightrange, it is presumed that the wafer in-plane uniformity in the plasmaprocess can be secured even when the power value of the supplied RFpower and the internal pressure of the process chamber are changed.

The aforementioned verification is directed to an embodiment in whichthe supplied gas is a mixed gas of the O₂ gas and the H₂ gas. However,according to another verification conducted by present the inventors, itwas confirmed that even when a mixed gas of an N₂ gas and an H₂ gas isused, the wafer in-plane uniformity in the plasma process can be securedin the aforementioned height range.

According to another verification conducted by the present inventors, itis presumed that even if parameters such as the gas flow rate, theheight width of the resonance coil, the winding pitch, the number ofturns, the frequency of the supplied high-frequency power, and the likeare changed in a practical range with respect to the conditions underwhich the above-described verification has been performed, similarverification results can be obtained with regard to the relationshipbetween the uniformity of the plasma density and the height positions.In addition, it is considered that the relationship between theuniformity of the plasma density and the height positions depends mainlyon the configuration of the plasma generation part. In theabove-described embodiment, the processing gas is supplied from the gassupply head 236 installed in the upper portion of the process chamber201. However, it is presumed that the similar verification result can beobtained even when a shape or position of the inlet port for introducingthe processing gas into the process chamber is different from that inthe above embodiment.

Furthermore, according to the plasma density distributions at the heightpositions (a) and (b) shown in FIG. 9, it can be noted that in the caseof the present embodiment, in the plane direction of the wafer, no largedeviation in the plasma density is generated in the range of 30 degreesto the left and right sides from the center of the wafer. That is tosay, by mounting the wafer in a predetermined region sufficiently awayfrom the resonance coil 212 to the center direction, it is also possibleto secure the wafer in-plane uniformity in the plasma process. In otherwords, it can be achieved by setting the winding diameter of theresonance coil 212 to a predetermined size sufficiently larger than thediameter of the wafer. Alternatively, it can be also achieved by using awafer having a predetermined diameter sufficiently smaller than thewinding diameter of the resonance coil 212. For example, in the presentembodiment, with respect to the resonance coil 212 having a windingdiameter of 500 mm, a wafer having a diameter falling within a range of30 degrees to the left and right sides from the center, namely a waferhaving a diameter of about 127 mm or less, may be used.

However, there is a limit in increasing the winding diameter of theresonance coil 212 from the viewpoint of cost, space and the like.Furthermore, in a case where a resonance coil having a winding numbersmaller than a predetermined magnitude is used, it is impossible toprocess a larger wafer. Therefore, in order to process a wafer having alarger diameter without increasing the winding diameter of the resonancecoil 212, the wafer may be processed at positions spaced apart by apredetermined distance (falling within a range of 38 to 138 mm in thepresent embodiment) downward from the lower end of the resonance coil212. For example, when the resonance coil 212 having a winding diameterof 500 mm is used to process a wafer having a diameter larger than about127 mm, the wafer may be processed at positions spaced apart by adistance of a predetermined range downward from the lower end of theresonance coil 212.

In the present embodiment, there has been described the example in whichthe wafer is processed at a position spaced apart by a distance fallingwith a range of 38 to 138 mm downward from the lower end of theresonance coil 212. However, the present disclosure is not limited tothis range. The height of the susceptor 217 (substrate mounting part)may be controlled to position the wafer 200 at such a height positionspaced apart downward from the lower end of the resonance coil 212 thatthe deviation (in-plane deviation) of the plasma density on the wafersurface in the plane direction falls within a predetermined allowablerange. For example, in-plane deviations of the plasma density at aplurality of height positions with respect to the lower end position ofthe resonance coil 212 are acquired in advance. Then, in accordance withthe allowable range of the in-plane deviation respectively set for eachprocess on the wafer, the height of the susceptor 217 is controlled soas to locate the wafer 200 at a height position at which the in-planedeviation falls within the allowable range of the in-plane deviation. Inthis case, the plasma density tends to grow high as the height positioncomes closer to the lower end of the resonance coil 212. Therefore, fromthe viewpoint of improving the process speed, it is preferable that thewafer 200 is located at a position closest to the lower end of theresonance coil 212 to the extent that the in-plane deviation is withinthe allowable range of the in-plane deviation.

Considering that the in-plane deviation of the plasma density is changedwhen changing the power value of the RF power supplied to the resonancecoil 212, the susceptor 217 may be controlled according to the powervalue of the RF power so that the height position of the wafer 200 isoptimized. For example, in-plane deviations of the plasma density at aplurality of height positions with respect to the lower end of theresonance coil 212 are acquired in advance for each power value of theRF power. Then, according to the power value of the RF power thus set,the height of the susceptor 217 may be controlled so as to locate thewafer 200 at a height position at which the in-plane deviation of theplasma density is an allowable in-plane deviation. Even in this case,from the viewpoint of improving the process speed, the wafer 200 may belocated at a position closest to the lower end of the resonance coil 212to the extent that the in-plane deviation is within the allowable rangeof the in-plane deviation. Similarly, from the viewpoint of improvingthe process speed, the plasma density may be generally set to becomehigher. Therefore, it is preferable that the power value of the RF poweris set to become the highest to the extent that the in-plane deviationis within the allowable range of the in-plane deviation.

Other Embodiments of the Present Disclosure

In the above-described embodiment, there has been described the examplein which the oxidizing process or the nitriding process is performed onthe surface of the substrate using plasma. However, the presentdisclosure is not limited to these processes and is applicable to anytechnique that performs a process on a substrate using plasma. Forexample, the present disclosure may be applied to a modifying process ora doping process on a film formed on a surface of a substrate, areducing process of an oxide film, an etching process of the film, anashing process of a resist, and the like, which are performed usingplasma.

INDUSTRIAL USE OF THE PRESENT DISCLOSURE

According to the present disclosure, when processing a substrate byplasma-exciting a processing gas, it is possible to reduce a deviationin density of plasma generated on a surface of the substrate, therebyimproving an in-plane uniformity in the substrate process.

What is claimed is:
 1. A substrate processing apparatus, comprising: asubstrate process chamber having a plasma generation space in which aprocessing gas is plasma-excited and a substrate processing spacecommunicating with the plasma generation space; a substrate mountingtable installed inside the substrate processing space and configured tomount a substrate thereon; an inductive coupling structure provided witha coil installed so as to be wound around an outer periphery of theplasma generation space; a substrate support table elevating partconfigured to raise or lower the substrate mounting table; a gas supplypart configured to supply the processing gas to the plasma generationspace; and a controller configured to be capable of controlling thesubstrate support table elevating part, based on a power value of ahigh-frequency power supplied to the coil, so that the substrate mountedon the substrate mounting table is positioned at a target heightaccording to the power value of the high-frequency power and spacedapart from a lower end of the coil.
 2. The apparatus of claim 1, whereina density of plasma generated at the target height while processing thesubstrate is uniform in a plane direction of the substrate.
 3. Theapparatus of claim 1, wherein the coil has a diameter larger than adiameter of the substrate.
 4. The apparatus of claim 1, wherein theplasma generation space is arranged above the lower end of the coil. 5.The apparatus of claim 1, wherein the plasma generation space isarranged between the lower end of the coil and an upper end of the coil.6. The apparatus of claim 1, wherein a density of plasma generated at aheight of the lower end of the coil has a distribution in a planedirection of the substrate where a density of the plasma generated atthe height of the lower end of the coil and above an outer edge portionof the substrate is higher than a density of the plasma generated at theheight of the lower end of the coil and above a central portion of thesubstrate.
 7. The apparatus of claim 1, wherein the target height isspaced apart by a distance of 38 mm or more downward from the lower endof the coil.
 8. The apparatus of claim 7, wherein the target height isspaced apart by a distance of 138 mm or less downward from the lower endof the coil.
 9. The apparatus of claim 1, wherein an electrical lengthof the coil is an integral multiple of a wavelength of thehigh-frequency power supplied to the coil.
 10. The apparatus of claim 3,wherein the diameter of the substrate is about 300 mm, and the diameterof the coil is 500 mm or more.
 11. The apparatus of claim 9, wherein thecoil has an electrical length which is one time the wavelength of thehigh-frequency power.
 12. The apparatus of claim 1, wherein thecontroller is configured to be capable of controlling the substratesupport table elevating part based on an allowable range of an in-planedeviation of a density of plasma in a plane direction of the substrate,which is set for each plasma process on the substrate mounted on thesubstrate mounting table.